Carbon-holder for electric-arc lights



R. C. MILLER.

CARBON HOLDER FOR ELECTRIC ARC LIGHTS.

APPLICATION FILED NOV. 7,1917

4 FIG.

INVENTOR RALPH C. MILLER Patented May 20, 1919.

UNITED STATES ENT ()FFICE" CARBON-HOLDER FOR ELECTRIC-ARC LIGHTS.

Specification of Letters Patent.

Patented May 20. 1919.

Application filed November 7, 1917. Serial No. 200,839.

To all whom it may concern Be it known that I, RALPH O. MiLLER, a citizen of the United States, residing at Los Angeles, in thecounty of Los Angeles and State of California, have invented new and useful Improvements in Carbon-Holders for Electric-Arc Lights, of which the following is a specification.

This invention relates to a carbon holder particularly adapted for use with moving picture projection machines.

It is often desirable to use the stub ends of the carbons used within the arc lights of moving picture projection machines and thereby lower the operating cost of the machine. It is the principal object of this invention to provide an extension. carbon holder within which the stub carbons may be gripped so that they may be used until they are exceedingly short.

Another object of this invention is to provide a holder for stub carbons which will allow the flame from the carbon to pass upwardly from the holder without damage thereto.

Other objects will appear hereinafter.

The invention is illustrated, by way of example, in the accompanying drawings in which: 1

Figure l is a view in perspective illustrating the carbon holding mechanlsm of a projecting machine and particularly disclosing the extension holders in place.

Fig. 2 is an enlarged view in perspective illustrating the two elements of oneof the extension holders in their assembled position and with a stub carbon in place. i

Fig. 3 is a view in front elevation illustrating the extension member.

Fig. 4 is a view in lower end elevation of the member shown in Fig. 3, particularly disclosing its gripping jaws and the clamping means.

Referring more particularly to the drawings, 10 indicates an adjustable carbon holding mechanism of common construction. This mechanism preferably consists of a rack casting 11 through which upper and lower rack rods 12 and 13 extend. To the opposite outer ends of the rack rods carbon holder knuckles 14; and 15 are secured. These knuckles as well as the rods are provided with adjusting rods 16 by which they may be manipulated. Secured to the knuc kles are carbon holders 17 and 18 with which the present invention is particularly concerned.

The carbon holders 17 and 18 are formed with a fastening shank 19 which is secured by screws 20 to an extension upon the holder knuckles. Formed integral with the shank 19 is a carbon clamping jaw 21. This jaw is formed with a V-shaped'clamping face 22 which is opposed by a similar clamping face upon a movable jaw member 23. The movable jaw member. is pivotally held in relation to the fixed member by a pivot screw 24. In order that the twojaws may be adjusted in relation to each other an extension 25 is made upon the movable jaw 23 and is adapted to be borne against by a clamping screw 26 which passes through a threaded opening in the shank 19 of the fixed. jaw. Due to this arrangement, the jaws may be adjusted as desired in relation to each other and the V-shaped clamping faces will permit carbons of various dimensions, from five-sixteenths of an inch to three-quarters of an inch to be gripped.

The carbon holders 1'? and 18 are adapted to directly grip carbon encils and also to grip extension holders 2 when the carbon has burned to a short length. These holders have straight cylindrical-shanks 28 adapted to be placed in theoriginal position of the carbon between the gripping faces of the jaws 21 and 23. Secured to the lower end of the shank 28 is a fixed gripping jaw 29 having a V-shaped gripping face 30 in opposition to a similar face 31 upon'a movable gripping jaw 32. The fixed and movable jaws are pivoted to each other by a screw33. The fixed jaw is formed with an extension 34 in opposition to a similar extension 35, upon the movable jaw and through which a clamping screw, 36 is positioned. This screw is adapted to bear against the-face of the extension 34 and force the jaws together. Attention is particularly directed to the fact that a space 37 occurs between the outer ends of the fixed and movable ja-Ws both upon the carbon holders 17 and 18 and the holders 27. This space is provided so that the flame from the short carbon may pass upwardly between these jaws and not impinge against the metal,'thus preventing the jaws from becoming obj ectionably heated, as would otherwise have been the case. The lower corners of the jaws, as particularly shown in Fig. 3, are rounded to provide additional clearance.

In operation, carbons of any desired diameter may be gripped between the jaws 21 and 23 of the holders 17 and 18 and thereafter regulated by the mechanism 10. As the lengthof the carbons is shortened the carbons may be removed and placed and'18.

It will thus be seen that by the use of the simple device here disclosed carbons of 'various diameters may be used with a project- 5 "ing apparatus and carbons of any desired length may. be held in operative position until a maximum amount of the carbon pencils have been burned away.

Whlle I have shown the preferred construction of my carbon holder for electric arc lights as now known to me, it Will be understood that'various changes in the combination, construction and arrangement of parts may be made by those skilled inthe art without departing from the spirit of my invention as claimed.

I claim:

In an electric are light, carbon holders, an extension holder having a straight cylindrical shank adapted to fit one of the carbon holders, a fixed gripping jaw secured to the lower end of the shank, a movable gripping 'ja'w pivoted to the fixed gripping jaw, said fixed jaw and said movable jaw having matmg extens1ons and set screw screw-seated through one of the extensions and engaging.

the other extension for'operating the movable jaw so that a short carbon maybe held in place by the movable jaw and against the end of the cylindrical shank and so that there will be a space alongside the short carbon between the point of the fixed j aw and the point of the movable jaw.

In testimony whereof I have signed my name to this specification.

RALPH c. MILLER. 

